The GPDP said it had decided to act after receiving "completely insufficient" answers to its questions about the firm's use of personal data.

In a statement, it said it had ordered "urgently and with immediate effect the restriction of the processing of data of Italian users by Hangzhou DeepSeek Artificial Intelligence and Beijing DeepSeek Artificial Intelligence, the Chinese companies that provide the DeepSeek chatbot service".

At the same time, the authority had opened an investigation, it said.

"The restriction measure, designed to protect the data of Italian users, follows the communication from the companies received today, the contents of which were deemed completely insufficient," it said.

On Tuesday, the agency announced it had raised questions with DeepSeek about how personal data was collected, from which sources and to what end, and where it was stored.

"Contrary to what was observed by the authority, the companies declared they do not operate in Italy and that European legislation does not apply to them," the statement on Thursday said.

The authority had also asked what kind of information was used to train DeepSeek's AI system and, if the data was scraped from the internet, to clarify how users of the service are informed about the processing of their data.

Based out of the eastern Chinese city of Hangzhou -- sometimes known as "China's Silicon Valley" -- DeepSeek sparked panic on Wall Street this week with its powerful new chatbot developed at a fraction of the cost of its competitors.

The Italian watchdog in December fined OpenAI 15 million euros ($15.6 million) over the use of personal data by its popular ChatGPT chatbot, but the US tech firm said it would appeal.

The investigation began in March 2023 when the GPDP temporarily blocked ChatGPT in Italy over privacy concerns, becoming the first Western country to take such action.